On Thu, 7 Nov 2019 14:00:47 +0100 Andreas Klinger <ak@xxxxxxxxxxxxx> wrote: > add support for parallax ping and laser ping sensors with just one pin > for trigger and echo signal. > > This driver is based on srf04. In contrast to it it's necessary to > change direction of the pin and to request the irq just for the period > when the echo is rising and falling. Because this adds a lot of cases > there is this individual driver for handling this type of sensors. > > Signed-off-by: Andreas Klinger <ak@xxxxxxxxxxxxx> A few really minor things inline. thanks, Jonathan > --- > drivers/iio/proximity/ping.c | 336 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 336 insertions(+) > create mode 100644 drivers/iio/proximity/ping.c > > diff --git a/drivers/iio/proximity/ping.c b/drivers/iio/proximity/ping.c > new file mode 100644 > index 000000000000..1a1fbb8ab0c2 > --- /dev/null > +++ b/drivers/iio/proximity/ping.c > @@ -0,0 +1,336 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * PING: ultrasonic sensor for distance measuring by using only one GPIOs > + * > + * Copyright (c) 2019 Andreas Klinger <ak@xxxxxxxxxxxxx> > + * > + * For details about the devices see: > + * http://parallax.com/sites/default/files/downloads/28041-LaserPING-2m-Rangefinder-Guide.pdf > + * http://parallax.com/sites/default/files/downloads/28015-PING-Documentation-v1.6.pdf > + * > + * the measurement cycle as timing diagram looks like: > + * > + * +---+ +------------------------+ > + * GPIO | | | | > + * ping: --+ +------------+ +---------------- > + * ^ ^ ^ ^ > + * |<->| interrupt interrupt > + * udelay(5) (ts_rising) (ts_falling) > + * |<---------------------->| > + * . pulse time measured > + * . --> one round trip of ultra sonic waves > + * . . > + * ultra +-+ +-+ +-+ . > + * sonic | | | | | | . > + * burst: ---------+ +-+ +-+ +----------------------------------------- > + * . > + * ultra +-+ +-+ +-+ > + * sonic | | | | | | > + * echo: ----------------------------------+ +-+ +-+ +---------------- Nice diagram ;) > + */ > +#include <linux/err.h> > +#include <linux/gpio/consumer.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/property.h> > +#include <linux/sched.h> > +#include <linux/interrupt.h> > +#include <linux/delay.h> > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > + > +struct ping_cfg { > + unsigned long trigger_pulse_us; /* length of trigger pulse */ > + int laserping_error; /* support error code in */ > + /* pulse width of laser */ > + /* ping sensors */ > + s64 timeout_ns; /* timeout in ns */ > +}; > + > +struct ping_data { > + struct device *dev; > + struct gpio_desc *gpiod_ping; > + struct mutex lock; > + int irqnr; > + ktime_t ts_rising; > + ktime_t ts_falling; > + struct completion rising; > + struct completion falling; > + const struct ping_cfg *cfg; > +}; > + > +static const struct ping_cfg pa_ping_cfg = { > + .trigger_pulse_us = 5, > + .laserping_error = 0, > + .timeout_ns = 18500000, /* 3 meters */ > +}; > + > +static const struct ping_cfg pa_laser_ping_cfg = { > + .trigger_pulse_us = 5, > + .laserping_error = 1, > + .timeout_ns = 15500000, /* 2 meters plus error codes */ Odd spacing? > +}; > + > +static irqreturn_t ping_handle_irq(int irq, void *dev_id) > +{ > + struct iio_dev *indio_dev = dev_id; > + struct ping_data *data = iio_priv(indio_dev); > + ktime_t now = ktime_get(); > + > + if (gpiod_get_value(data->gpiod_ping)) { > + data->ts_rising = now; > + complete(&data->rising); > + } else { > + data->ts_falling = now; > + complete(&data->falling); > + } > + > + return IRQ_HANDLED; > +} > + > +static int ping_read(struct ping_data *data) > +{ > + int ret; > + ktime_t ktime_dt; > + s64 dt_ns; > + u32 time_ns, distance_mm; > + struct platform_device *pdev = container_of(data->dev, > + struct platform_device, dev); to_platform_device() > + struct iio_dev *indio_dev = iio_priv_to_dev(data); > + > + /* > + * just one read-echo-cycle can take place at a time > + * ==> lock against concurrent reading calls > + */ > + mutex_lock(&data->lock); > + > + reinit_completion(&data->rising); > + reinit_completion(&data->falling); > + > + gpiod_set_value(data->gpiod_ping, 1); > + udelay(data->cfg->trigger_pulse_us); > + gpiod_set_value(data->gpiod_ping, 0); > + > + ret = gpiod_direction_input(data->gpiod_ping); > + if (ret < 0) { > + mutex_unlock(&data->lock); > + return ret; > + } > + > + data->irqnr = gpiod_to_irq(data->gpiod_ping); > + if (data->irqnr < 0) { > + dev_err(data->dev, "gpiod_to_irq: %d\n", data->irqnr); > + return data->irqnr; > + } > + > + ret = devm_request_irq(data->dev, data->irqnr, ping_handle_irq, > + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, > + pdev->name, indio_dev); > + if (ret < 0) { > + dev_err(data->dev, "request_irq: %d\n", ret); > + return ret; > + } > + > + /* it should not take more than 20 ms until echo is rising */ > + ret = wait_for_completion_killable_timeout(&data->rising, HZ/50); > + if (ret < 0) > + goto err_reset_direction; > + else if (ret == 0) { > + ret = -ETIMEDOUT; > + goto err_reset_direction; > + } > + > + /* it cannot take more than 50 ms until echo is falling */ > + ret = wait_for_completion_killable_timeout(&data->falling, HZ/20); > + if (ret < 0) > + goto err_reset_direction; > + else if (ret == 0) { > + ret = -ETIMEDOUT; > + goto err_reset_direction; > + } > + > + ktime_dt = ktime_sub(data->ts_falling, data->ts_rising); > + > + free_irq(data->irqnr, indio_dev); > + > + ret = gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW); > + if (ret < 0) { > + mutex_unlock(&data->lock); > + return ret; > + } > + > + mutex_unlock(&data->lock); > + > + dt_ns = ktime_to_ns(ktime_dt); > + if (dt_ns > data->cfg->timeout_ns) { > + dev_dbg(data->dev, "distance out of range: dt=%lldns\n", > + dt_ns); > + return -EIO; > + } > + > + time_ns = dt_ns; > + > + /* > + * read error code of laser ping sensor and give users chance to > + * figure out error by using dynamic debuggging > + */ > + if (data->cfg->laserping_error) { > + if ((time_ns > 12500000) && (time_ns <= 13500000)) { > + dev_dbg(data->dev, "target too close or to far\n"); > + return -EIO; > + } > + if ((time_ns > 13500000) && (time_ns <= 14500000)) { > + dev_dbg(data->dev, "internal sensor error\n"); > + return -EIO; > + } > + if ((time_ns > 14500000) && (time_ns <= 15500000)) { > + dev_dbg(data->dev, "internal sensor timeout\n"); > + return -EIO; > + } > + } > + > + /* > + * the speed as function of the temperature is approximately: > + * > + * speed = 331,5 + 0,6 * Temp > + * with Temp in °C > + * and speed in m/s > + * > + * use 343,5 m/s as ultrasonic speed at 20 °C here in absence of the > + * temperature > + * > + * therefore: > + * time 343,5 time * 232 > + * distance = ------ * ------- = ------------ > + * 10^6 2 1350800 > + * with time in ns > + * and distance in mm (one way) > + * > + * because we limit to 3 meters the multiplication with 232 just > + * fits into 32 bit > + */ > + distance_mm = time_ns * 232 / 1350800; > + > + return distance_mm; > + > +err_reset_direction: > + mutex_unlock(&data->lock); > + free_irq(data->irqnr, indio_dev); > + > + if (gpiod_direction_output(data->gpiod_ping, GPIOD_OUT_LOW)) > + dev_dbg(data->dev, "error in gpiod_direction_output\n"); > + return ret; > +} > + > +static int ping_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *channel, int *val, > + int *val2, long info) > +{ > + struct ping_data *data = iio_priv(indio_dev); > + int ret; > + > + if (channel->type != IIO_DISTANCE) > + return -EINVAL; > + > + switch (info) { > + case IIO_CHAN_INFO_RAW: > + ret = ping_read(data); > + if (ret < 0) > + return ret; > + *val = ret; > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_SCALE: > + /* > + * maximum resolution in datasheet is 1 mm > + * 1 LSB is 1 mm > + */ > + *val = 0; > + *val2 = 1000; > + return IIO_VAL_INT_PLUS_MICRO; > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_info ping_iio_info = { > + .read_raw = ping_read_raw, > +}; > + > +static const struct iio_chan_spec ping_chan_spec[] = { > + { > + .type = IIO_DISTANCE, > + .info_mask_separate = > + BIT(IIO_CHAN_INFO_RAW) | > + BIT(IIO_CHAN_INFO_SCALE), > + }, > +}; > + > +static const struct of_device_id of_ping_match[] = { > + { .compatible = "parallax,ping", .data = &pa_ping_cfg}, > + { .compatible = "parallax,laserping", .data = &pa_ping_cfg}, > + {}, > +}; > + > +MODULE_DEVICE_TABLE(of, of_ping_match); > + > +static int ping_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct ping_data *data; > + struct iio_dev *indio_dev; > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(struct ping_data)); > + if (!indio_dev) { > + dev_err(dev, "failed to allocate IIO device\n"); > + return -ENOMEM; > + } > + > + data = iio_priv(indio_dev); > + data->dev = dev; > + data->cfg = of_match_device(of_ping_match, dev)->data; of_device_get_match_data > + > + mutex_init(&data->lock); > + init_completion(&data->rising); > + init_completion(&data->falling); > + > + data->gpiod_ping = devm_gpiod_get(dev, "ping", GPIOD_OUT_LOW); > + if (IS_ERR(data->gpiod_ping)) { > + dev_err(dev, "failed to get ping-gpios: err=%ld\n", > + PTR_ERR(data->gpiod_ping)); > + return PTR_ERR(data->gpiod_ping); > + } > + > + if (gpiod_cansleep(data->gpiod_ping)) { > + dev_err(data->dev, "cansleep-GPIOs not supported\n"); > + return -ENODEV; > + } > + > + platform_set_drvdata(pdev, indio_dev); > + > + indio_dev->name = "ping"; > + indio_dev->dev.parent = &pdev->dev; > + indio_dev->info = &ping_iio_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = ping_chan_spec; > + indio_dev->num_channels = ARRAY_SIZE(ping_chan_spec); > + > + return devm_iio_device_register(dev, indio_dev); > +} > + > +static struct platform_driver ping_driver = { > + .probe = ping_probe, > + .driver = { > + .name = "ping-gpio", > + .of_match_table = of_ping_match, > + }, > +}; > + > +module_platform_driver(ping_driver); > + > +MODULE_AUTHOR("Andreas Klinger <ak@xxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("PING sensors for distance measuring using one GPIOs"); > +MODULE_LICENSE("GPL"); > +MODULE_ALIAS("platform:ping");
